#include <stdio.h>
#define _CRT_SECURE_NO_WANINRS 1

int main() {
	int n = 0;
	int i = 0;
	int stemp = 1;
	scanf("%d", &n);
	for (i = 1; i <= n; i++) {
		stemp = i * stemp;
	}
	printf("%d\n", stemp);
	return 0;
}
